Looks like a nice install. Have no idea why your subj line calls this a HILLBILLY AC...
With the walls so thin even your install may suffer some with the wild vibrations you may experience. Hoping the installed bracket supports all of the unit weight and not depend much on ears like a strong window unit install does.
Others have put more of the Window AC Units inside the trailer for better support. Some have even sit the inside heavy part of the AC unit on a table top arrangement all boxed in of course.
Be interesting how the thin walls are going to hold up over time supporting the whole AC unit overhang weight..
May be just fine for you but may deserve some close watching on how well it holds up.
My 120VAC WESTPOINTE 8000BTU Home Window unit runs just fine on my 2KW Honda generator.
Just my observations
Roy Ken